Correction system and correction method of signal measurement

Abstract

A correction system and a correction method of signal measurement are provided. In the method, a transmitted signal and a received signal are divided into a plurality of transmitted signal groups and a plurality of received signal groups according to a time length, respectively. The received signal is related to a signal received after the transmitted signal is transmitted, and the transmitted signal is a periodic signal. A plurality of to-be-evaluated groups are selected from the received signal groups according to a correlation between the transmitted signal groups and the received signal groups. The correlation corresponds to a delay between the transmitted signal and the received signal. The signal energy of the received signal is determined according to the signal energy of the to-be-evaluated groups. Accordingly, the accuracy of signal measurement can be improved.

What is claimed is: 
     
       1. A correction method of signal measurement, comprising:
 dividing a transmitted signal and a received signal into a plurality of transmitted signal groups and a plurality of received signal groups according to a time length, respectively, wherein the received signal is related to a signal received after the transmitted signal is transmitted, and the transmitted signal is a periodic signal; 
 selecting a plurality of to-be-evaluated groups from the plurality of received signal groups according to a correlation between the plurality of transmitted signal groups and the plurality of received signal groups, wherein the correlation corresponds to a delay between the transmitted signal and the received signal, and the step of selecting the plurality of to-be-evaluated groups further comprises:
 classifying close correlations between the plurality of transmitted signal groups and the plurality of received signal groups to form a plurality of delay categories; 
 selecting one to-be-evaluated category from the plurality of delay categories according to quantities of correlations in the plurality of delay categories; and 
 determining the plurality of to-be-evaluated groups according to the plurality of received signal groups corresponding to the to-be-evaluated category; and 
 
 determining signal energy of the received signal according to signal energy of the plurality of to-be-evaluated groups. 
 
     
     
       2. The correction method of signal measurement according to  claim 1 , wherein the step of selecting the to-be-evaluated category from the plurality of delay categories comprises:
 selecting the one comprising a greatest number of correlations included in the plurality of delay categories as the to-be-evaluated category. 
 
     
     
       3. The correction method of signal measurement according to  claim 1 , wherein before forming the plurality of delay categories, the correction method further comprises:
 using the largest one of the correlations of a plurality of sampling points between each received signal group and the corresponding transmitted signal group as a representative of the correlations between the received signal group and the corresponding transmitted signal group. 
 
     
     
       4. The correction method of signal measurement according to  claim 1 , wherein the step of determining the plurality of to-be-evaluated groups according to the received signal groups corresponding to the to-be-evaluated category comprises:
 classifying close signal energy of the plurality of received signal groups corresponding to the to-be-evaluated category to form a plurality of energy categories; and 
 selecting the one comprising a greatest number of signal energy from the plurality of energy as a new to-be-evaluated category. 
 
     
     
       5. The correction method of signal measurement according to  claim 1 , wherein before dividing the transmitted signal and the received signal into the plurality of transmitted signal groups and the plurality of received signal groups, the correction method further comprises:
 playing the transmitted signal and receiving sounds to generate a sound received signal, wherein the periodic signal is a sinusoidal signal; and 
 eliminating interference in the sound received signal according to a signal characteristic of the transmitted signal to obtain the received signal, wherein the signal characteristic is related to a periodic change of the periodic signal, and the received signal comprises the signal characteristic. 
 
     
     
       6. The correction method of signal measurement according to  claim 1 , wherein the step of selecting the plurality of to-be-evaluated groups from the plurality of received signal groups according to the correlation between the plurality of transmitted signal groups and the plurality of received signal groups comprises:
 using fast cross correlation to determine the correlation between one of transmitted signal groups and a corresponding one of received signal groups. 
 
     
     
       7. The correction method of signal measurement according to  claim 1 , wherein at least one sampling points in one of the received signal groups is overlapped with at least one sampling points in another of the received signal group, or
 at least one sampling points in one of the received signal groups is overlapped with at least one sampling points in another of the transmitted signal groups is overlapped with at least one sampling points in another of the transmitted signal groups. 
 
     
     
       8. A correction system of signal measurement, comprising:
 a processing device, loaded with and executing a plurality of modules, wherein the plurality of modules comprises:
 a signal division module, configured to divide a transmitted signal and a received signal into a plurality of transmitted signal groups and a plurality of received signal groups according to a time length, respectively, wherein the received signal is related to a signal received after the transmitted signal is transmitted, and the transmitted signal is a periodic signal; 
 a screening module, configured to select a plurality of to-be-evaluated groups from the plurality of received signal groups according to a correlation between the plurality of transmitted signal groups and the plurality of received signal groups, wherein the correlation corresponds to a delay between the transmitted signal and the received signal, and
 the screening module classifies close correlations between the plurality of transmitted signal groups and the plurality of received signal groups to form a plurality of delay categories, selects one to-be-evaluated category from the plurality of delay categories according to quantities of correlations in the plurality of delay categories, and determines the plurality of to-be-evaluated groups according to the plurality of received signal groups corresponding to the to-be-evaluated category; and 
 
 an energy determining module, configured to determine signal energy of the received signal according to signal energy of the plurality of to-be-evaluated groups. 
 
 
     
     
       9. The correction system of signal measurement according to  claim 8 , wherein the screening module selects the one comprising a greatest number of correlations included in the plurality of delay categories as the to-be-evaluated category. 
     
     
       10. The correction system of signal measurement according to  claim 8 , wherein the screening module selects the largest one of the correlations of a plurality of sampling points between each received signal group and the corresponding transmitted signal group as a representative of the correlations between the received signal group and the corresponding transmitted signal group. 
     
     
       11. The correction system of signal measurement according to  claim 8 , wherein the screening module classifies close signal energy of the plurality of received signal groups corresponding to the to-be-evaluated category to form a plurality of energy categories, and the screening module selects the one comprising a greatest number from the plurality of energy categories as a new to-be-evaluated category. 
     
     
       12. The correction system of signal measurement according to  claim 8 , further comprising:
 a speaker device, configured to play the transmitted signal, wherein the periodic signal is a sinusoidal signal; and 
 a sound receiving device, configured to receive sounds in response to playing of the transmitted signal to generate a sound received signal, wherein the modules further comprise:
 an interference elimination module, configured to eliminate interference in the sound received signal according to a signal characteristic of the transmitted signal to obtain the received signal, wherein the signal characteristic is related to a periodic change of the periodic signal, and the received signal comprises the signal characteristic. 
 
 
     
     
       13. The correction system of signal measurement according to  claim 8 , wherein the screening module uses fast cross correlation to determine the correlation between one of transmitted signal groups and a corresponding one of received signal groups. 
     
     
       14. The correction system of signal measurement according to  claim 8 , wherein at least one sampling points in one of the received signal groups is overlapped with at least one sampling points in another of the received signal group, or
 at least one sampling points in one of the received signal groups is overlapped with at least one sampling points in another of the transmitted signal groups is overlapped with at least one sampling points in another of the transmitted signal groups.